Research On The Key Technologies Of Low Altitude Radio Fuze

Fuze is one of the most important components of modern weapons, which function is to control the optimum detonating position of ammunition. The performance of fuze has great influence on the terminal damage effect. Different from conventional fuze, the object of low altitude radio fuze is earth surface. It is necessary to do the research on target property and find a distance measuring arithmetic which can be applied in low altitude radio fuze.In these circumstances, supported by NUDT Innovation Foundation, this dissertation selects low altitude radio fuze as research object, and concentrates its attention on the research of key technologies, such as target properties, fuze channel property, echo model, distance measuring arithmetic and digital simulation system design, etc. The main contents and contributions of this dissertation are as follows:1. The target properties of low altitude radio fuze are discussed at length. The interaction between electromagnetic waves and ground is analyzed. The definition of back scattering coefficient and its influence on echo signals are discussed. After analyzing the influence of several factors on back scattering coefficient, the scattering characteristic measuring method and principle of ground target are given. And some statistical models of back scattering coefficient are compared.2. The signal features of terrain return are discussed in depth. The probability density function of amplitude-fluctuation under different condition is analyzed. The equal-Doppler equation, the equal-distance equation, and the boundary equation of electromagnetic wave irradiating area are deducted. Based on these deductions, the power waveform of echo signals is derived. In the end, a rang-Doppler terrain return power spectrum density (PSD) computation method is introduced in this paper. This method is validated by computer simulation and the simulation results are analyzed.3. The characteristic of low altitude radio fuze are discussed in depth. It is concluded that low altitude radio fuze channel is a doubly-spread channel, through which a signal propagates will experience both time delay and frequency spreading. The definition of dynamic characteristics function and characteristic parameter of fuze channel are presented. The echo model from different target and the expression of terrain return equation are proposed.4. The conception of relative standoff distance is proposed and the feasibility of its application in low altitude radio fuze is analyzed. A distance measuring algorithm based on process measuring is proposed. The algorithm principle and realization are discussed in detail. Considering the peculiar applying situation of distance measuring algorithm, theoretical analysis and simulation validation are made on the anti-jamming performance. A combined distance measuring algorithm based on both process measuring and distance prediction is proposed which gives a integrated solution to low altitude radio fuze distance measurement.5. According to the development trend of fuze and the design philosophy of software radio fuze, a digital simulating system of low altitude radio fuze has been established. The overall design principle and modular programming method are discussed in detail. A real-time range-doppler power spectrum density computation method is presented. And the simulation of coherent correlated terrain return for general pulse fuze is fulfilled with method of Zero Memory Nonlinearity and Spherically Invariant Random Process.